| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.14 | 1.29 | 1 |
| 2024 | 1.15 | 1.5 | 0.89 |
| 2023 | 1.04 | 1.13 | 0.88 |
| 2022 | 0.96 | 1.18 | 0.84 |
| 2021 | 1.69 | 2.94 | 1.06 |
| 2020 | 1.42 | 1.85 | 1.13 |
| 2019 | 1.08 | 1.39 | 0.72 |
| 2018 | 0.83 | 0.98 | 0.67 |
| 2017 | 0.94 | 1.05 | 0.87 |
| 2016 | 0.88 | 1.01 | 0.78 |
| 2015 | 1.25 | 1.98 | 0.94 |
| 2014 | 0.91 | 1.32 | 0.8 |
| 2013 | 1.26 | 1.94 | 0.93 |
| 2012 | 1.92 | 2.35 | 1.5 |
| 2011 | 3.28 | 6.16 | 1.66 |
| 2010 | 4.64 | 7.55 | 2.35 |
| 2009 | 6.36 | 7.83 | 3.71 |
| 2008 | 7.37 | 14.8 | 2.79 |
| 2007 | 10.05 | 15.84 | 4.73 |
| 2006 | 3.12 | 5.39 | 2.03 |
| 2005 | 2.06 | 2.49 | 1.68 |
| 2004 | 3.71 | 5.56 | 2.34 |
| 2003 | 4.16 | 4.85 | 3.47 |
| 2002 | 4.99 | 5.81 | 4.26 |
| 2001 | 5.14 | 7.23 | 2.69 |